Polarization

According to Malus' Law, the intensity of light passing through a polarizer is given by:

where is the angle between the light's polarization direction and the polaroid's transmission axis.

The intensity decreases at each polaroid sheet according to the angle between the axes. After passing through all three polaroids, the intensity of the emergent light is , as each polarizer reduces the intensity by a factor related to the cosine of the angle between its axis and the polarization direction.